You do know that's a busted myth, right? And it's easily provable: relax your sphincter right now. Even try pushing and, if you didn't already feel the need to go, you'll see that you won't **** yourself.

Actually, the ******** yourself is only with very traumatic deaths. Basically when you body gets a super adrenaline/dopamine rush before you die. It causes your system to empty itself so it has nothing to focus on but basically surviving. Then if you die shortly after it still vacates your system purely because the process was already started. There is a reason the phrase, scared the **** out of me exists.